Interaction of solitary wave with a concentric structure with multiple porous outer walls

This paper gives an analytical solution for a plane solitary wave interaction with a concentric structure with coaxial multiple-layered porous walls. An analytical solution is obtained based on shallow water wave theory and eigenfunction expression matching. Furthermore, a series of simultaneous equations are used to determine po-tential coefficients. The accuracy of the present model is verified by comparing its output with published results. Meanwhile, the impact of various important parameters (i.e., the number of porous walls, annular spacing and porosity of walls) with respect to wave forces and relative wave height is examined. It is sufficient to safeguard the inner cylinder by using two-three porous walls. For multiple walls with different porous-effect parameters, the arrangement of the selected porous effect parameters has a marginal influence on the force of the imper-meable cylinder. However, the minimum wave run-up on it can be observed when the coefficient of the porous walls increases from the outside to the inside. In addition, an impermeable cylinder with two concentric porous walls is investigated owing to its higher application prospects.